Frequency dependent gamma-ray irradiation response of Sm2O3 MOS capacitors

Abstract

The frequency dependent irradiation influences on Sm2O3 MOS capacitors have been investigated and possible use of Sm2O3 in MOS-based radiation sensor was discussed in this study. To examine their gamma irradiation response over a range of doses, the fabricated MOS capacitors were irradiated up to 30 grays. Capacitance–Voltage (C–V) measurements were recorded for various doses and the influences of irradiation were determined from the mid-gap and flat-band voltage shifts. In addition, the degradations of irradiation have been studied by impedance based leakage current–voltage (J–V) characteristics. The results demonstrate that J–V characteristics have not been significantly change by irradiation and implying that the excited traps have a minor effect on current for given dose ranges. However, the frequency of applied voltage during the C–V measurements affects the irradiation response of devices, significantly. The variations on the electrical characteristics may be attributed to the different time dependency of acceptor and donor-like interface states. In spite of the variations on the device characteristics, low frequency measurements indicate that Sm2O3 is a potential candidate to be used as a dielectric layer in MOS based irradiation sensors.